Self-adjusting pump



Dec. 25, 195] Filed Feb. 24, 1950 T. C. GOODALE SELF-ADJUSTING PUMP 4 Sheets-Sheet 2 PATENT AGENT Dec. 25, 195] /N VE N TOR THOMAS CGOODALE 58 Q 59 AGENT Dec. 25, 195] T c, GQQDALE SELF-ADJUSTING PUMP 4 Sheets-Sheet 4 Filed Feb. 24, 1950 E M Wm m \m mg R C m 1 m M W w W w m M 6 \Q o:

n9 \kg M h@ v@ @2 Q9 O 2 4 9 a 1 w a v- 0 mo m6 mm Q9 I I mm m mfihn PATENT AGENT Patented Dec. 25, 1951 UNITED STATESMPATENT OFFICE 2,579,817 SELF-ADJUSTING PUMP Thomas G. Goodale, Oakland, Calif.

Application February 24, 1950, Serial No. 146,047

3 Claims. I

The present invention relates to pumps and aims to provide a pump that is adapted to automatically adjust its operation in accordance with the varying loads that it may encounter during practical performance.

More specifically it is an object of the invention to provide a pump that is adapted to adjust its operation to the variations in the pressure that the pump has to overcome, such that the WOl'k performed with each pumping stroke remains substantially the same. 4

Another object of the invention is to provide a pump that may be operated with equal power no matter how much the load may vary that is encountered by said. pump.

It is still another object of my invention to provide a pump automatically adapted to vary the effective amplitude of its piston stroke in inverse relation to variations in the load which it encounters.

Additionally, it is an object of-my invention to provide a pump that is automatically effective to vary the leverage of its actuating mechanism in such a manner as to suit the mechanical advantage of said actuating mechanism to the loads encountered.

Furthermore it is an object of my invention to provide a pump that is of particular aptitude as actuating unit for presses, elevators, vises, aircraft landing flaps and any other mechanism that may be hydraulically operated.

These and other objects of my invention will be apparent from the following description of the accompanying drawings which illustrate certain preferred embodiments thereof and wherein:

Figure 1 is a side elevation of a pump constructed in accordance with my invention,

Figure 2 is a plan view of the same pump,

Figure 3 is a horizontal section taken along line 3-3 of Figure 1, illustrating a component of the pump viewed in the direction of the arrows associated with line 3-3,

Figures 4, 5, 6 and 7 are fragmentary vertical sections through the pump taken along line 4-4 of Figure 2 and illustrating different operational positions thereof, and

Figure 8 is a side elevation of a modified embodiment of the invention with certain outer parts broken away to expose the structure underneath.

Having first reference to Figures 1 and 2, two pistons 26 and 2| are slidably received within opposite ends of a cylindrical bore 22 provided in a block 24. Whenever the pistons 20 and 2! are withdrawn from one another liquid is drawn into the space 25 between the inner end surfaces of said pistons through an intake channel 26 that is controlled by a suitable inlet valve 21 and whenever the pistons and 21 are forced toward one another, the liquid may escape from chamber 25 through a discharge channel 28 that is controlled by a suitable outlet valve 29.

To actuate the pistons 25 and 2| an interponent connects the outer end of the upper piston 20 pivotally to an actuating lever 35 at an intermediate point of said lever that is identified by the reference numeral 31. The right end 38 of said lever 36 is free and forms the actuating handle of said pumpiits left end, however, is extended in transverse direction to form a narrow rectangular frame 39, as best shown in Figure 2. Projecting laterally from the side members 39a and 39b of said frame at the near ends thereof are two stub shafts 40a and 401) that form the fulcrum 4! of the actuating lever 36 and which are suitably journaled in the upper ends of a pair of arms 42a and 42?), respectively, that rise from the upper face of the block 24. Provided in the inner faces of said side members 39a and 391) are shallow arcuate grooves 44a and 44b, respectively, within which are slideably received the opposite ends of a transverse stud 45. Said stud is firmly secured to the upper end of a link 46 and is also rotatably supported in the arms 41a and 41b of a U-shaped adapter member 41. Interposed between the remote end member 390 of the rectangular frame 39 and said adapter member 41 is a coil spring 50 which urges the stud into the near corner 38d of the rectangular frame 39 wherein it is co-axia'l with the stub shafts 40a and 40?) that form the' fulcrum of the actuating lever 36 (Figures 4 and 5).

The lower end of the link 46 is pivoted to one end 54 of a lever 55 that is pivotally supported at its center point 56 from an arm 51 which de pends from the lower face of the block 24. An interponent 58 pivotally connects the other end 59 of said lever 55 to the outer end of the lower piston 2 I.

While the spring is arranged to urge the stud 45 into a position co-axial with the stub shafts 40a and 40b of the actuating lever 3%, as previously pointed out, the actual position of said stud 45 during operation of the pump is determined by the pressure prevailing in the discharge channel 28 beyond the outlet valve 29. Having again reference to Figures 1 and 2, a conduit 6!! leads from a point of said channel 28 beyond valve 29 into a hydraulic cylinder 6| that may suitably be formed in the block 24, and within which is slidably received a plunger 52. An interponent 63 connects the outer end of said plunger 52 pivotally to a lateral projection 65 of the aforementioned link 46. Thus, whenever the pressure in the discharge channel 28 beyond the valve 25 increases, said pressure forces the plunger 62 further out of cylinder 6! and said plunger 52, in turn, swings the link 46 in counter-clockwise direction about its pivotal connection 54a with lever 55 against the urgency of spring 5!), and in this manner moves the stud 45 to the left and out of co-axial alignment with the fulcrum 4| of the actuating lever 35 into positions such as illustrated in Figures 6 and 7.

When the described pump is operated with no appreciable pressure existing in the discharge conduit 28 beyond the outlet valve 29, the spring 5c is effective to keep the plunger 62 fully inserted within the hydraulic cylinder 5|, so that the stud 45 is positioned intermediately of and in co-axial alignment with the stub shafts 45a and 4% that form the fulcrum of the actuating lever 35, as shown in Figures 4 and 5. When the lever 36 is actuated with the stud 45 positioned in this manner, it reciprocates the upper piston 29 between an extreme inner position wherein its front end is situated at about the center of the cylindrical bore 22, as illustrated in Figure 4, and an extreme outer position wherein its front end is situated close to the upper end of said bore, as shown in Figure 5. Upon the lower piston 21, however, the actuation of lever 35 remains with out effect due to the position of the stud 45 in co-wxial alignment with the fulcrum M of said lever 36. Hence, the lower piston 2! remains stationary with its front surface located about half way between the center and the lower end of the bore 22, as shown in both Figures 4 and 5. Thus, as long as there is no appreciable pressure in the discharge line 28 beyond the valve 29, the

pump of my invention operates in the manner of an ordinary single piston pump as if the piston 26} were its only piston, and delivers with every downstroke of the actuating arm 35 a volume of fluid through the valve 29 that is eoual to the cross-sectional area of the bore 22 times the full length of the distance over which the piston travels from its'extreme outer position (Figure to its extreme inner position (Fi ure 5).

As the pressure in'the line 23 beyond the valve 29 increases, however. due to the o eration of the pump such as is the case when the pump is employed to operate hydraulic presses, Vises, elevators or the like, the pressure built u in the conduit 28 acts upon th plunger 52 within the hydraulic cylinders! through the line ii! and pushes said plunger out of said cylinder to a de ree de ending upon the pressure prevailin in line 28. The plunger 62, in turn, forces the link 45 to the le t. as viewed in Figures 1, 6 and 7, moving the stud 45 out of axial alignment with the ulcrum M of the actuating lever 36. As soon as the stud 45 is moved out of axial alignment with the fulcrum of the actuating lever 39, operation of said lever imparts to said stud a reciprocating movement which it transmits through the link 46 to the lever 55. As a result thereof the piston 2l' is withdrawn from the bore 22 whenever the piston 25 is pushed deeper into said bore by a distance determined by the extent to which the pressure developed in line 28 has moved the stud to the left of the fulcrum 4| of the actuating lever 35. Thus, with the stud 45 in the position illustrated in Figures 6 and 7, actuation of the lever 36 is effective to reciprocate the upper plunger 20 between the previously defined extreme inner and outer positions in the same manner as hereinbefore described, but at the same time causes the lower plunger 2 l to move in unison with plunger 20 in a manner which reduces the effective stroke amplitude of the upper piston 20 to an extent determined by the eccentricity of stud 45. Thus, the volume of fluid forced through the outlet valve 29 with every operating stroke of the actuating lever 36 equals the cross-sectional area of the bore 22 times the difference between the distance traveled by the upper piston 20 and the distance traveled by the lower piston 2| so that the same stroke of the actuating lever 36 forces a lesser amount of fluid through the V valve 29, depending upon the pressure prevailing in line 28. By appropriately proportioning the strength of the spring 50 the pump of my invention may be adapted to proportion the volume of fluid discharged with every stroke of the actuating lever, in accordance with the pressure developed in line 23, in such a manner that the amount of work performed by the pump with every stroke of the actuating lever remains sub stantially the same so that the pump may at all times be operated with the same effort disregarding any variations in the load that it may encounter. By dimensioning the arcuate grooves 44a and 44b in frame 39 in such a manner that their left ends position the stud 45 a distance to the left of the fulcrum 4! of the actuating lever 36 that is equal to the distance between the fule crum of lever 55 and its pivotal connection 54a with the link 46, the pump of my invention may be adapted to suspend effective operation whenever the pressure developed in line 28 beyond valve 25 has reached a predetermined maximum; and vice versa, whenever the pressure in line 23 decreases, the effective stroke amplitude of the pistons is automatically increased in that the spring 55 is enabled to force plunger 52 deeper into the cylinder Bl, so that larger volumes of fluid are forced through the pump with every actuating stroke of lever 35 while the amount of work performed with each stroke remains the same.

The pump construction illustrated in Figure 8 differs from the pump represented by Figures 1 to '7 in that it comprises only a single piston while the previously described embodiment of my invention employed two pistons 20 and 2|. Referring specifically to Figure 8, said piston 85 is slidably disposed-within a cylindrical bore 81 provided in a block 88. Liquid may be drawn into said cylindrical bore through an intake channel 89 controlled by a suitable inlet valve 90 and may escape from said bore through a discharge channel 91 controlled by a suitable outlet valve 92. The outer end of the piston 85 is pivotally connected to the lower end of a link and firmly mounted in the upper end of said link 94 is a stud 95 which engages slidably an arcuate slot 96 provided in an intermediate portion of a pump actuating lever 98. The free right end of said actuating lever forms the operating handle 99 of the pump while its opposite end m0 is rotatably supported by an arm liil that rises from the upper end of the block 88 at the left side thereof. Suitably journaled on a stud [02 that projects laterally from said link 9 is a rod I03. For guidance the left end of said rod is slidably received within a suitable aperture I04 that may be provided in the aforementioned arm 10!. An expansion spring I65 coiled around the rod [03 is interp sed betwee the right face of arm ml and an adapter I03a mounted upon said rod I03 to the left of stud I02. Said spring I05 urges the link 94 in clockwise direction, as viewed in Figure 8, to hold the stud 95 yieldably in the right corner of the arcuate slot 96. Likewise journaled upon the stud I02 is a link I06 that is pivotally connected to the plunger I01 of a hydraulic cylinder I08 which is connected to the discharge line 9| of the pump at a point beyond the outlet valve 92 by means of a flexible conduit I I 0. Thus, whenever the pressure in the discharge line 9| increases, the plunger I01 of the hydraulic cylinder moves the rod I03 to the left against the force of the coil spring I05 and in this manner shifts the pivotal connection 95 between the actuating lever 98 and the link 94 from the remote position illustrated in Figure 8 closer to the fulcrum I00 of said actuating lever, and in this manner decreases the amplitude of the effective piston stroke produced by actuation of-the lever 98. Hence, the same work performed by the actuating lever 98 is efiective to force less liquid at greater pressure through the outlet valve 92.

into the high pressure line 9| beyond said valve.

Due to the fact that the pump of my invention may be arranged in such a manner that the power required to operate said pump remains substantially the same disregarding wide variations in the load which the pump may encounter, said pump may be actuated by relatively small motors without danger of overloading said motors and is therefore of particular aptitude for use in hydraulically operated devices such as presses, elevators, vises, landing flaps of airplanes and the like.

While I have explained m invention with the aid of certain preferred embodiments thereof, it will be understood that I do not wish to be limited to the specific constructional details shown and described by way of example which may be departed from without departing from the spirit and scone or my invention. Thus, it will be evident to those skilled in the art that the described variations in the effective stroke amplitude of the pistons may be accomplished by means other than hydraulic cylinders that are operated by the pressure variations in the discharge conduit.

I claim:

1. A pump comprising a chamber, a discharge line leading from said chamber, a first piston slidably received within said chamber at one point thereof, a second piston slidably received within said chamber at another point thereof, a first actuating lever for reciprocating said first piston, a second actuating lever for reciprocating said second piston, guide means associated with said first lever, a link pivotally connected with one end to said second lever, a stud mounted in another end of said link and arranged to engage said guide means, spring means arranged to urge said stud within said guide means into a predetermined position relative to said first lever, a hydraulic cylinder operatively connected to said discharge line, and a plunger slidably received Within said hydraulic cylinder and operatively connected to said link means in a manner effective to force said stud out of said predetermined position whenever an increase in pressure within said discharge line moves said plunger out of said hydraulic cylinder.

2. A pump according to claim 1 wherein the predetermined position of said stud is arranged to coincide with the fulcrum of said first actuating lever.

3. A pump comprising a cylinder, a discharge conduit leading from said cylinder, an outlet valve provided in said discharge conduit, first and second pistons slidably disposed within said cylinder at the opposite ends thereof, a first actuating lever pivotally connected with said first piston, a second actuating lever pivotally connected with said second piston, a guide means associated with said first actuating lever and extending from its fulcrum to a point a predetermined distance removed from said fulcrum in a direction opposite to its pivotal connection with said first piston, a link having an end pivotally connected to said second actuating lever at a point removed from its fulcrum in a direction opposite to its connection with said second piston, pivot means mounted in another end of said link and engaging said guide means, spring means arranged to urge said pivot means within said guide means into a position coincident with the fulcrum of said first actuating lever, and hydraulic means responsive to increase in the pressure in said discharge conduit beyond said outlet valve and operatively connected to said link for forcing said pivot means in a direction counter to said spring means.

1 THOMAS C. GOODALE.

REFERENCES CITED The following references are of record in the ifile of this patent:

UNITED STATES PATENTS Number Name Date 54,291 Cameron May 1, 1866 943,987 McCarty Dec. 21, 1909 943,988 McCarty Dec. 21, 1909 950,076 McCarty Feb. 22, 1910 984,688 McCarty Feb. 21 1911 1,894,834 Sillince Jan. 1'7, 1933 1,983,229 Hillier et a1 Dec. 4, 1934 2,160,687 Stubbs May 30, 1939 2,172,103 Kotaki Sept. 5, 1939 

